Compressor and fuel control system for high-pressure gas turbine power plants



Sept. 29, 1953 N. c. PRICE Y v COMPRESSOR AND FUEL CONTROL `TEM FOR HIGH-PRESSURE GAS TURBINE PO PLANTS 5 Sheets-Sheet l Filed June 5, 1948 INVENTOR. NATHAN C. PRIQE Sept. 29, 1953 N. c. PRICE COMPRESSOR AND FUEL CONTROL SYSTEM POR HIGH-PRESSURE GAS TUREINE POWER PLANTS 3 Sheets-Sheet 2 Filed June 5, 1948 INVENTOR. NATHAN C. PRICE gent Sept. 29, 1953 N, C, PRlCE 2,653,446

COMPRESSOR AND FUEL CONTROL SYSTEM FOR HIGH-PRESSURE GAS TURBINE POWER PLANTS Filed June 5, 1948 5 Sheets-Sheet 5 INVENTOR.

NATHAN C. PRICE Patented Sept. 29, 11.953x

COMPRESSOR AND FUEL CONTROL SYS- TEM FOR 'HIGH-PRESSURE G'AS TURBNE' POWER PLANTS Nathan. C.; Price, St. Helena, 'Calif., .assignon to Lockheed. Aircraft Corporation, Burbank,l Calif..v

Application June 5, 1948,SeriaI-No. 31,348v

12 claims; l

This invention relates to-internal combustion .gasy turbine powerplantsv and rela-tes more particularly` to means for controlling `the compressors and fuel;Y supply systems of such power plants intended forY the propulsion of aircraft.

Gas turbine power plants designed for the propulsionof.- aircraft-must operate under widely varying altitude pressures and at different speeds, that -isf'they must operate eiiiciently at vrelata'vely.slow speeds, at approximately sea-level altitudes as well as at high speeds at altitudes einsam-30,1000: feet. Where axial nowl compressors are employed'- much difliculty is encountered'. in: maintaining the correct relationship betweenthe volumetric rate of air flowA and thev rotational speed generally termed the Q/N ratio For example, at relatively low altitudes of ig-htrwhererthe airisd'ense, ythe iirstv stages of compression tend to become overloaded while therear or high` pressure stages tend to turbine; Thei turbines of Ythe engines. are designed to operate, within a given Q/N rangeand where the compressor outputfluctuates excessively due to ambient air pressure conditions,v etc., the eiiiciency off *the turbine is. correspondingly adversely.- affected. The. diculty` maybe alleviated by .regulating the speed of the Iowpressure stages ot' the compressor system or by regulating theV angleofs' .attack ofthe low pressure compressor'iinpeller-.blades Both of:v these ex- .pedients involve; rather-heavy and?` expensive modcationss ofthev compressors and wherel` the bladinggangles: arev regulable extremely complicated' mechanismsv and controlsf must be employed.. Furthermore, such regulationI ot lthe speed -or angie or' attack off vthe low-- pressure bladingdoesrnotfof itself* maintain or regulate the turbine temperatures or the air-iuell'ratio reuuiredirm emcient power plantV operation.

- Itis an4 object of the present vinvention to provide a simple, reliable, and inexpensivesystem; for' maintaining: the substantially correct Q/N ratio in the compressor andi turbine off'a high pressurer gas lturbine power plant; 'I-h'e system of.r the present invention does: not require expensive: or complicated modification of the compressors but on=v the,A other handi's characterized: by simpler lby-pass ducts' lea-ding from an intermediate point in thecompressor system to either. the-turbine' or the.L turbinet exhaust pipe. i Anotherobject ofthe invention :is to provide a. system; off; the, character.z mentionedi in which valves' ior.` controlling the compressorl by-pass ductsare. operatedinresponse to: a rotational Speed governor.: so; thatthe.- quantity of air rbeing .2; by-passed from theintermediate point of; the `compressorsystem tothe turbine or turbine exhaust is a functionA oi the rotationalspeed of thefcompressor and, turbine. Thus vthe. speed responsive governor andthexby-pass. valves regulatedf .therebym serve. to; automatically maintain the- .substantiallycor-rect .volumetric rate: of: air now and-rotationals speed: ratioV during .operation ofA thejplant'v under varying conditions.

Another object' otthe invention. is to provide a. 4system .offthex characterA referred toi incorporating a-mainually regulable fiuel: supply. organization for selectively delivering fuel to the expansion chamber'otjthe. turbine andto a .supplemental: combustion-zone at the-exit. ofthe expansion chambervformcreasect power output While maintaining the delivery of fuel2 to: Athe primary combustion chamber. The system of the invention is adapted for the control of a turbo power plant having a prima-ry combustion chamber between. the discharge of the compressor system: and.i the turbine, an intermediate fuel injection means at the expansion zone of the turbine, and. a supplemental fuel injection means inthe: tailapipe, and.- the system embodies a manual control lever or the. equivalent' that may be operatedi to. provide for the variable deliveryof. fuelftothese three. areas asthe. conditons:` of operationog the power plant require. Furthermore; the control lever, or. the equivalent, is also operable to gradually open thevalves of. the; compressor vby-pass'` duct as the .fuel flow settings. arev reduced below the value Vof full primary fuel. injection thereby relating the volumeoff` air by-passed around the second:v stage compressor and primary combustion chamber to thevolumeof the fuel injected. to preserve vthe correct relationship between the Q/N ratio and the air-fuelratio.

`A- further: object of' the invention toprovide the control system of the character herein described embodying;` means responsive to thetemperaturein the turbine for automatically regulating the.: air-fuelratio and to. limit the temperature developed. in `the turbine;

Other: objectivest and: advantages will become apparent fromfthe following detailed: description of a typical: preferred embodiment Vthroughout whichdescription reference' will be made to the accompanying drawings in which? "Iiig/ure-k 1 is aside elevation of a gas turbine power plant embodying features of one form of the-invention with the lower portion ofr the power plant appearing in longitudinal cross section;

Figure 2 is an end' view ofv the engine taken substantially as indicated by line 2-2 on Fig- Fure 1;

Figure 3 is an enlarged fragmentary, longitudinal sectional View of the turbine portion of the engine illustrating the intermediate and supplemental fuel injection means and a portion of the compressed air by-pass system of another form of the invention;

Figure 4 is an enlarged fragmentary transverse sectional view taken substantially as indicated by line 4-4 on Figure 3;

Figure 5 is a developed sectional view of a row of turbine stator blades employed for the injection of fuel and compressed air in the structure of Figure 3 with arrows indicating the direction of iiow of the propellent gases and air during the low speed turbine operation;

Figure 6 is a View similar to Figure 5 with the arrows indicating the direction of flow during higher turbine speed operation; and

Figure 7 is a diagrammatic view illustrating the control system of the invention as applied to the power plant of Figure l.

In the drawings I have illustrated the invention associated with r incorporated in a gas turbine power plant having first and second stage axial flow compressors, an annular combustion chamber, a multistage turbine, and a turbine exhaust nozzle for producing a propulsive jet of the combustion gases and compressed air. It is to be understood that the invention may be applied to or embodied in power plants of this general class varying considerably in design, construction and power` output rating and, therefore, the invention is not to be construed as limited to the speciiic power plant or other details illustrated.

The power plant includes a compressor housing I@ containing the first and second stage compressors I and I2. The forward end of the housing I@ is open to receive the rammed air and the housing is a generally cylindrical tubular assembly. The first stage compressor I I includes a hollow rotor i3 which gradually increases in diameter in the rearward direction and which carries a multiplicity of rows of impeller blades I4. The impellers lll operate between rows of stator blades i secured in the housing Ill. The opposite ends of the rotor I3 are carried in suitable bearings I5 and l1 so that the rotor rotates coai axially in the housing IS.

The second stage compressor I2 includes a rotor I8 mounted in the housing IS in axial alignment with the first stage compressor rotor I3. Spaced bearings I9 and 26 carry the rotor IE for rotaf.

tion. The rotor IB is of rearwardly inceasing diameter and is spaced within an annular or tubular wall 2I. A plurality of rows of impeller blades 22 on the rotor I8 operate between rows of stator blades 23 on the wall 2l. Bevel gears 24 and 25 are secured to the adjacent opposing ends of the rotors I3 and IS respectively and cluster pinions 26, carried by radial shafts 2l, mesh with the gears to provide a speed reducing drive between the two compressors. An annular duct 28 leads from the discharge of the rst stage compressor I I to the inlet of the second stage compressor I2 and an annular duct 30 leads from the outlet of the second stage compressor I 2 to the primary combustion chamber 3 I.

The primary combustion chamber 3| is an annular enclosure dened by the wall of a rearwardly tapering casing 32 and a shroud or wall 33 spaced within the casing. The forward end of the chamber 3I receives the compressed air from the high pressure compressor duct 3B while the rear end of the chamber discharges through a nozzle ring 34 into the turbine 35. Fuel injecting jets 36 are arranged in the forward portion of the combustion chamber 3i and are supplied with fuel by an annular manifold 3l extending around the chamber. One or more electrical gniters 38 eX- tend into the combustion chamber to ignite the fuel.

The turbine 35 includes a substantially cylindrical casing 39 extending rearwardly from the combustion chamber casing 32 and the turbine rotor 4&3 operates within the casing 33. The rotor 43 is fixed to a central tubular shaft 4I extending rearwardly from the second stage compressor rotor I. As best illustrated in Figures 1 and 3, the turbine rotor li@ is of rearward diminishing eX- ternal diameter and its periphery is spaced from the turbine casing 33 to leave an expansion zone of rearwardly increasing capacity. A plurality of rows of hollow impeller blades or buckets 42 of heat resistant, high strength material, project from the rotor Llc and operate between rows of stator blades 43 projecting inwardly from the wall of the casing 39. The first row of blades 42 are preferably of the impulse type while the other blades 42 are of the reaction type and have cambered airfoil sections. The intermediates or stator blades 43 are stationarily mounted to project radially inward into the turbine expansion zone.

In the embodiment of the invention shown in Figure 3, one of the intermediate rows of stator blades "13 is or special construction to provide for the introduction into the expansion zone of both fuel and bypassed compressed air from the compressor system, it being understood that the invention contemplates the introduction of fuel at one row of stator blades 43 and introduction of compressed air at either the same or another row of blades. The special row of stator blades, which I will designate 433, may be the third stage intermediates, that is the stator blades projecting into the space between the second and third rows of turbine impeller blades 42. The blades 43 have their roots welded or otherwise fixed to cylindrically curved plates 44 which conform generally with the internal surface of the casing 39. rEhe circumferential margins of the plates 44 have stepped rims 45 which space the plates from the surface of the casing to leave insulating air spaces 45. The fuel and air introducing blades 439 are likewise carried by a plate or ring l1 having similar marginal rims 48 which mate with the stepped rims d5 of the plates 44 and which cooperate with the casing 33 to space the ring 4l from the casing and leave an annular air space 53.

The stator blades 435 are hollow, each having an internal cavity or passage 5I which extends from the blade tip to the air space 5D. As will be later described compressed air from an intermediate point in the compressor system I I-I2 is supplied to the annular space 5S under certain conditions of operation of the power plant and this air ows out through the passages 5I of the blades 433 to discharge at the blade tips. The blades 43B are further provided with slots 52 and 53 in their concave and convex sides respectively. rihe slots 52 and 53 serve to discharge the compressed air from the blade passages 5i into the turbine expansion zone. As best illustrated in Figures 5 and 6 the slots 52 and 53 are located in the leading edge portions of the blades 439, the slots 52 being somewhat closer to the leading edgesQthan theslotsi. The slots-53am shaped and located=' to directthe f compressed. airy rearwardtyfxandi Iaterallyf.asindicated.` by the arrows in."E'igures 5.'.and'` 6..anctzare.nozzle. like aper- 'turesfbeingsomewhat restricted. at. their exit.

The slots 52 .in the concave side of thefblades 43u facalaterallyf.andusomewhat forwardly or toward the leadingedgesoatthe blades. Theleading-.edge portion ofveach blade :530 has an axially extending .tuhularport-ion or tube-'5%. and. therear. wall: ofzthis tube mayiformthe `forward-4 boundary offrthe. aclacen-t slotorzoricevB 2.

@During startingA and low-speed operation oi* the power-:planti the propellent .v gases-*fof 'combustion and air underL pressure.discharge.frorrrthesecond stagerotor'blades 42 inthe direction. indicated. by thearrowaXin Figure''. .Under-.such conditions air under pressure discharges through the slots 52 .as weil. as.throughrtheasiotsl.531110 flow]- rearwardi-y acrossithe blade.- surfaces 'together with they propellent gases .asindicatedr by the arrows atitheslotsin-Figure5. f However, during. medium andthigh. speed1operationloi the. power plant the propellant ,gases stream fir-omi `.the second 4stage rotor blades42 substantra-lily.A thedirection. indicated-bythe arrowsY in Eigurex 6. Underthese conditions the.:propellent-A gases.l enterithe .slots 53 and flow transversely through the bladek passages i todischargethrough the-.slots-.53together withsthel underpressure delivered' bythe passagea-El. This action-'is indicated bythe arrows atx/therslots.51% and A53 `fir1-Figure 6. .The exact direction 'offthe arrowsHX-i and:A Y', representingdirection. offgas" flow, .will-vary. according to therow 'oilst'ator varies chosenfon airafuel injection., but the.'filiustratedcasei-is representative for third stage statorsfiirra turbineof four stages.

The above-mentioned@ tubular portions or tubes 54'; at thcleadingedge:portions of the blades. 43S receive fuelirfirornc a4 flueb manifold '-55 at the eXn teriorl ofiithe turbine. Infpracticetherv tubes 54 or extensions: thereon kpass radiallyl outward throughl the-.turbine wall -to connect with the manifold. 55. 'Thefmanifol'dl .55: has branchesv 56' whichi delivery Euer. under. pressurev tol couplings 5.11 on thedouter ends ofthe tubes`54i A- .row' of fuel iniectingvorfdischarging-orifices'58.is provi-ded ineach tubef54lf to dischargefthefuel'i into-'the-expansionlzoneof the-turbine 35. ii'he orifices 58 roperrat the, convex sides "off theblades` 430i immediately adj acenttheic leadingv edges. The fuel introduced at theorices 58 burns inthe air and gasimixture-x liowingA through the expansion. zone of4 -the turbine-'tog increase.` thed power output of the. engine-atfhigher rotative speed,- andr the injectedrair produces a beneficial volumetric filling eect in the latter stages of vthe turbine during relatively lowV speed operation.

i Infthe-formi of the invention illustratedin Figure 1-vwhereI the by-passedcompressed air is discharged'intothetail' pipe 60' the space `50 at .the roots off then blades 430 may befclosedand the slots 52 andA 53 maybe omitted. However, the fuel injecting4 tubes 5l! and their orifices 58 together wtih they manifold 55,` etcg, remain as above ldescribed for the injection of'-` intermediate fuel' intothe; expansion zone Voithe turbine35'.

-Y'Thepower plant further-includesthe tail' pipe or exhaust pipe A)littwhich leads.' from the rear end of; the turbine' housing 39 to thev propulsivegnozzle N. The nozzle N is "shown in Figure 1 in a rather diagrammatic manner;v it being Aapparent that anyappropriate propulsivar nozzle may be `employed although a variable area type will gen-- erallybe-A preferred, laterdiscussed in connection-v ywith-.liigure 7. The .taitpipe Sitios of ysubstantial lengthv andiv the'portion -ofttheixpipe adjacent the turbine 35 is employed as. assupple.- mental combustion chamber when additional thrust. is required. Means is provided for. intro..- ducing fueL .into :this.-supplemental` combustion chamber. Inwthe dra-wingsI hare;.showr1 a pipe 61| "extending rearwardlythroughthe secorrdfstage compressor rotor i8: andy theV turbineshaft. tzto the apex end of .the turbine-rotor 40. The: pipe 6 l: passes through` a packing gland QuinA theior- `ward portion ofthe compressor yrotor :l 8v and. con.- tinuescvoutwardly through. theA wall". of the housing-.lf0 to. connect withY the fuelusupply `and' con.- trol system to be subsequently described". The rear end of .the pipe. 61| discharges into; .radial ports 62 in the apex'of-theturbine rotor f401wh-ich in turn .discharge intoa capa,63 on the rotor. 1A circular row ofi-ports 64 in the cap-Sinjectsfthe fuel under pressure rearwardly andlateraIIyLfinto the supplemental combustion chamber. Thefnel .thus injected from the apex'of the turbine rotor is thoroughly'admixed` with the air and combustionf gases exhausting from the turbine .35(

In the embodiment of the inventoinv illustrated in Figures 1 and 2 the compressed {by-pass systemincludes one or more lay-passlducts: @5i leading from an intermediate pointoruzone of. the compressor means ||`-l|2 'tofy the-tail 4pipa-"60; The particular structurev illustrated hasftwo substantially diametricallyV opposite ductss65 extending .rearwardly withinthe' compressor housing il!) from the: above described dischargen passagez28 of the rststage compressor Il.. Thetwol ducts .65' communicate with; only relativelyv short. portions of the compressor passage- 23 to withdraw a part of the compressed air'output 'of the-first stage compressor .I l, the balance 'of the-passage 28 being unobstructed toA discharge into the. intake of the second stage compressor l2. The forward portionsof the by-passvv ducts 65 may-follow the internal wall-ofthe housing tito be spaced from thecompressor wall 2'I and then passoutwardlyi .through openings in 'the' housing 0 to continue rearwardly at' the exteriorV 'ofthe engine.` 'The ducts65 continuey rearwardly past'the combustion. chambercasing 32 to. connect with air discharge.- loriniecticn fittings 65; The ducts S5 Vanditheir ttings Bit are preferably connected by slip-joints 61 which permit thermal expansion and contraction ofthe assemblies. 'As best showniin4 Figure 2 of the drawings the:v fittings '66 flare laterally tand turn inwardlyfto the tailp-ipe 60, their broadenedv or flared ends [being-partially circular to conformto. the tail pipe. While the ttings Vlili are extendedor ilared laterally. they are .gradually restricted in the axial. direction. The rear ends of thettingsf' communicate with and discharge-.through circumferentiallyiextending openings. 68.-

the wall .of theita-il-:ppe 6.0. The. openings.: 6,8. have: asconsiderablewcircumferential extent to` distribute the air through the greater part or thezcircumferenceizof the-.tail pipee 60 toassurea substantial uniform fiowV of the compressed air. into thestreamof combustion gases. and' air .exhausting fromL the turbinei-35i Part of the relatively.'coolcompressed air.` intro! duced at.the openings 68 tends to'owalong the internal surface of the tailpipe- 60V tol form -a protective or insulating boundary/flayerfof air. The air.adniittingv openings `68= areina tran-s'- Verse or diametric plane adjacent but slightly rearwardy 4of Vthe turbine 35: 'so that the compressed air from an intermediate pointinthe l compressor system |||2 is discharged into the supplemental combustion chamber region above described.

A valve 69 is provided in each duct 65 to regulate the compressed air iiow therethrough. I prefer to employ streamlined butterfly valves 69 that are slightly unbalanced in the downstream direction to be responsive to air flow through the ducts. The unbalancing of the streamlined Valves 69 is such that the valves tend to move to the open position in response to air flow through the ducts 65. The valves 89 are operated or controlled by the manually regulable automatic control system to be subsequently described.

In the construction illustrated in Figures 3 to 6 inclusive, the compressed air withdrawn or by-passed from the intermediate point in the compressor system ||-|2 is introduced into the expansion zone of the turbine 35 at the abovedescribed stator blades 430. In this case the by-pass ducts 65 connect with ttings 10 at the turbine 35. Slip-joints 1| between the ducts 85 and the ttings 10 provide for thermal expansion and contraction of the duct assemblies. The fittings 10 are similar to the fittings 86 previously described, being flared or broadened to engage a substantial distance around the turbine casing 39. The rear ends of the ttings 10 may be secured to raised bosses or seats 12 on the casing 39 l and a series of circumferentially spaced openings 13 extend through the seats 12 and the Wall of the casing 39 to communicate with the interiors of the fittings. The openings 13 serve to connect the above-described annular space 58 with the by-pass duct fittings 10 so that the compressed air is supplied to the space 50 at a multiplicity of points. This air flows through the internal passages of the blades 430 to discharge fro-m the slots 52 and 53 and the tips of the blades as hereinabove described. The by-pass ducts 85 ernployed in the construction of Figures 3 and 4 are equipped with the valves S9Vfor controlling the diversion of compressed air from the intermediate points in the compressor system to the expansion zone of the turbine 35. The fuel tubes I54 of the blades 430 may pass radially outward through the space 50, the openings 13 and the wall of the fittings to the couplings 5'! as shown in Figure 3.

The control system of the invention serves to govern the delivery of fuel to the pri-mary combustion chamber fuel jets 36, and fuel Atubes 54 of the blades 439 and the pipe 8| for supplying fuel to the supplemental fuel orifices 84 and the system operates to automatically regulate the Valves 69 of the compressed air by-pass ducts 85 to maintain the volumetric flow entering the second compressor l2 at a value substantially proportional to the rotative speed of the compressor I2 during changes in velocity of flight at constant altitude and during changes in flight altitude. The fuel supply and control organization of the system includes a suitable fuel tank and a motor driven pump 18 for pumping fuel from the .tank through a main supply line l1. A fuel con- -dui-t or line 18 leads to the primary fuel injecting manifold 31, a similar line 19 leads to the intermediate fuel injecting manifold 55 and a third fuel line 80 extends to the pipe 6| of the supplemental fuel supply means. Remotely controlled valves A, B and C are connected between the main fuel supply pipe 11 and the respective lines 18, 19 and 80.

'I'he three valve mechanisms A, B and C may be identical and corresponding reference numerals are applied to corresponding parts of the same. Each valve includes a pair of aligned cylinders 8| and 82 and a piston rod 83 extending into opposite ends of the cylinders. Pistons 84 and 85 are secured on the rods 83 and operate in the cylinders 8| and 82 respectively. The cylinders 8| serve to pass or conduct fuel and are connected in the fuel lines 18, 19 and 80. Thus corresponding ends of the cylinders 8| have independent communication with the fuel supply pipe 11 While the other ends of the cylinders have outlet ports 86, 81 and 88 respectively discharging into the lines 18, 19 and 80. Needle valves 98 are carried by the rods 83 or pistons 84 and are adapted to cooperate with the related ports 89, 81 and 88 to control the fuel flow to the lines 18, 19 and 80 respectively. The ports 86, 81 and 88 are preferably shaped to properly receive the needle valves 90. The pistons 84 are received in the cylinders 8| with large sidewall clearance to permit the flow of the liquid fuel past or around the pistons for the purpose to be later described. Accordingly, the hydraulic force imposed upon the pistons 84 tending to close the valves 90 is responsive to the rate of flow of fuel past the pistons 84.

The cylinders 82 with their pistons 85 constitute the remotely controlled actuators of the valves A, B and C. Air under pressure from the compressor system |-|2 of the power plant may serve as the actuating medium pressing upon the pistons 85 to open the fuel valves 90. In Figures l and '7 I have shown a pipe or line 9| leading from the discharge passage 30 of the second stage compressor |2 and `carrying the air under pressure for the actuation of the valves A, B and C. The air pressure line 9| has two branches 92 and 93, the branch 92 extending to the inner end of the cylinder 82 of the valve A and the branch 93 extending to the inner ends of the cylinders 82 of the valves B and C. The delivery of air pressure to the valve actuating pistons 85 is controlled by a manually and automatically operable pressure bleed system and to insure a desired independent operation of the valves B and C it is preferred to incorporate restrictions 94 in the parts of the line 93 extending to the cylinders 82 of the valves B and C so that bleeding of pressure from one or both of the cylinders of valves B and C does not appreciably affect the pressure in the other cylinder, or in certain other parts of the pneumatic system to be described later. The pressure line 92 of the valve A has an extension or branch 95 extending to a manually regulated bleed valve D. A pressure bleed line 98 extends from the cylinder 82 of the fuel control valve B to a bleed valve E and a similar bleed line 91 extends from the cylinder 82 of the valve C to a bleed valve F. The bleed valves D, E and F may be identical and reference numerals are applied to their corresponding parts.

Each pressure bleed valve D, E and F includes a cylinder 98 and a piston 99 operable in the cylinder. Each cylinder 98 has a lateral bleed port |00 and the pistons 99 are movable between positions where they close the ports |00 and positions where the ports are open. The lines or pipes 95, 96 and 91 from the actuating cylinders 82 of the valves A, B and C communicate with their respective cylinders 98 at points spaced axially from the bleed ports |00 being in communication with the ends of the cylinders While the ports |00 are spaced inwardly from the cyl- 9 inder ends.. In the preferred form of the invention a Vsingle manually movable lever, or the equivalent, servesV to actuate or regulate the valves D, E and F. As shown in Figure 7 this manually actuated member is .in the form of a lever associated with a rotatable cam v|02 so-as to turn or rotate the same. The cam |02 turns within a substantially cylindrical or arcuate wall |03 which has spaced openings |04 receiving cam followers |05. The followers |05 .cooperate with` the active .surface-of the cam |02 and extend into the cylinders 98. Flanges or heads |06 are provided on the followers. |05 to operate in the cylinders 98 and coiledA compressionsprings |01 are engaged between the follower heads and the pistons 99 -to transmit movement from the followers to the pistons. The profile of the cam |02 is such that the cam is turnable between a power off position where the bleed ports |00 of the three valves D, E and F areall -open and a full power position where the ports |00 of the three valves are closed. The cam |02 issuch that the vfollower .|05 of. the valve rD may be operated individually to control or` close the port |00 and is such that further movement of the lever |0| resultsv in successive operation Aof the valves E and F to fclose their bleed ports |00 while maintaining the valve D actuated. Reverse movement of the lever |0`I from the full power position rst results in opening up the port |00 of the valve F,`then causes opening of the port T00 of the valve E .and yfinally allows opening of the port |00 of the valve D. During this returnmovement of the cam |02 the air pressure actingv on the .pistons 99 moves the pistons to the .position where they uncoverthe ports |00.

From the foregoing it will be seen that the delivery or injection of fuel into the primary combustion chamber 3|., the intermediate .fuel tubes 54 and the ysupplemental fuel orifices 64 is 4controllable vby the manual lever |0|.. When the cam |02 is turned to a .position where it actuates the piston l99 of the valve D outwardly, the port 00 is closed or partially closed and air pressure builds up in the .inner 4endl of .the cylinder '82 of -the valve A to move the piston `85 against the. force exerted on the piston 84 4bythe fuel under pressure. Thismovement of the pistons 8l and 85 retracts the .needle valve 9.0 .fromthe .port 86 to permit the flow of uid or anincreased 'flow of fuel to the primary combustion chamber 3|. When the control or throttlelever |-0| is moved to a position where airr pressure in the cylinder 9.8 of the valve D shifts the piston 9.9 clear of or vpartially clear .off the port |00,-pres sure in the inner end of the cylinder 82V of valve Ais .reduced and fuel under ,pressure acting `on the piston 84 of valve A moves the needle valve 90 toward the port 86 to restrict or cut4 oi the flow of fuel to the primary combustion chamber 3|. The cam |02 operates the bleed valves E and F in the same mannerl .to control their related or respective fuel control valves B and C. Accordingly, the lever I0! maybe operated to lseparately control the injection of fuel into ,the primary combustion chamber 3| and when additional thrust or power output is desired, the lever IUI may be operated to provide for the introduction of fuel into the expansion .zone of the turbine and then into the supplemental combustion chamber. With the primary combustion fuel system bleed valve D vfully closed, the valve .E may be regulated by manipulation of the lever |'0| to vary theintroduction of fuel into the expansion zone of 'the turbine, .and with the `10 valves D and E fullyclosed the lever |0I may be operated to vary or regulate the introduction of fuel into the supplemental combustion chamber.

In accordance with the invention the injection of fuel into the primary combustion chamber 3| is controlled or regulated by a means responsive to the rotational speed of the turbine and compressors il and l2. A valve ISE' is interposed in the above-described air pressure line S2 of the yprimary fuel control valve A. The valve |07 may Ybe of the .piston type to include a cylinder |08 and a piston E09 operable .in the cylinder. The cylinder |08 is connected in the line 92 to have the upstream section of the line communicate with an end of the cylinder and to have the downstream section of the line connect with a port i0 spaced axially from said end-of the cylinder. The piston 109 is movable in the cylinder |03 'to control the port |.|.0, being urged to an open position clear of the .port by the air .pressure admitted to said end of the cylinder. The above-mentioned rotational speed responsive means may talee the form of a fly-ball governor driven by one of the above-described radialshafts 2'! of the engine and arranged to cooperate with a projecting end of the valve piston |09. The parts are related .so that upon an lincrease in the speed of rotation of the turbine rotor 40, the governor urges the piston |09 inwardly, tending to close Ithe port l l0. On the other hand the air under ,pressure admitted to the cylinder |98 Yfrom the upstream end of the line 92 urges the piston I 09 to the open position. The action of the .governor in restricting the port l0 upon an increase in the rotational speed of the power plant reduces the flow of air under pressure to the cylinder 82 of the Valve A so that the fuel under pressure flowing through the cylinder '8| of the valve A urges the needle toward the closed position to restrict the delivery of fuel to the prim-ary combustion chamber 3|. It Will be observed that this. speed responsive control of the primary combustion chamber fuel injection system does not affect the delivery of fuel to the expansion Zone of the -turbine 35 or to the supplemental combustion chamber.

The control system further includes a temperature responsive means for control-ling the air-fuel ratio at the several points or zones of fuel injection-and for limitingthe temperature developed in the primary combustion. chamber 3| and turbine 35. This temperature responsive means includes a vave ||2 for controlling the actuating air pressure supply line 9|. The valve H2 may be of the needle type arranged to control a .port I3 in a valve Vbody or case |4 interposed -i-n the air pressure line 9|. A compression spring I5 is arranged to urge .the valve l2 toward the closed position andanactuating lever H8 is connected with the :projecting portion of the valve. The temperature responsive means further includes a suitable. thermostat located in the primary combustion chamber 3| vor ina hot portion of the turbine 35. In the particular case illustrated Lthe thermostat .is arranged to extend into the combustion chamber 3| and comprises a heat resistant rtube ||6 having a substantial -coeicient of thermal expansion and a rod of silica, or the like, having a low coefficient of expansion ysecured to the inner end of the tube. The inner end of the tube I6 is closed while the outer. endA of the tube is open. The rod |'i passes outwardly lthrough the open outer end of the tube ||16 and wcooperates with the lever l||8. The parts are conx'Stlllcted and related so that upon expansion of the tube I6, resulting from an increase in combustion chamber temperature, the rod l moves inwardly and the spring pivots the lever ||l and moves the valve ||2 toward the closed position. Such restriction of the port i3 reduces the air pressure in the lines 92 and S3 and in the cylinders 82 so that valves A, B and C operate to reduce the rate of fuel delivery to their respective fuel injectors. Conversely, upon a reduction in combustion chamber temperature the thermostat tube H5 contracts and the rod I moves outwardly to pivot the lever H8 against the action of the spring I5. This moves the valve l2 away from its port H3 admitting an increased flow of air pressure to the lines 92 and 93 and to the cylinders $2 so that the valves A, B and C provide for an increased iiow of fuel to their respective fuel injectors. From the foregoing it will be seen that the temperature responsive means operates to automatically limit the temperature developed in the engine, serving to maintain the temperature within a safe and practical range.

It is a feature cf the invention that the abovedescribed valves E39 which control the compressed air bleed or oy-pass ducts 65 are associated with and automatically operated by the above-described manually controlled bleed valve D and the temperature responsive means. `Flach valve t9 is equipped with a lever l2@ operated by a servomotor. As diagrammatically illustrated in Figure '7 the servo-motors are of the diaphragm type, comprising chambers i2 and flexible diaphragms |22 extending across the mouths of the chambers. Rods |23 on the diaphragme |22 are pivotally connected with the adjacent or related valve lever |26. A pipe or line |24 branches from the above-described air pressure line 92 of the primary fuel control valve A and extends to the diaphragm chambers |2| to supply air pressure thereto. The line |24 communicates with the line 92 at the upstream side of the rotational speed responsive valve lill so that the by-pass valves S9 are iniiuenced or affected by operation of the speed responsive means IG? so the positions of the valves |59, or the operative areas of the ducts 65 as determined by the Valves 69, are a function of the rotational speed. Furthermore, it will be seen that closing of the bleed valve D by the cam |52 increases the effective air pressure in the lines Q2 and |24. As above described, this results in increased. opening of the primary fuel control valve A and further serves to iiex the diaphragms |22 outwardly to move the by-pass valves 69 toward the closed position. Conversely, when the bleed valve D is open, the pressure in the lines E32 and |24 is reduced and the diaphragms |22 dex inwardly to move the valves 69 toward the open position. As a result the valves 69 of the by-pass ducts 65 progressively open as the primary combustion chamber fuel iiow setting is reduced below the value for full primary fuel injection. This provides for an increased diversion of compressed air from the intermediate point in the compressor system l 2 to the turbine expansion zone or tail pipe at periods of low primary fuel consumption.

It is believed that the operation of the system of the invention will be understood from the foregoing detailed description wherein the mode of operation of its several components is fully described. With the power plant in opera-tion the manual lever |li| may be shifted or adjusted at will to vary primary combustion chamber fuel injection and to provide for the introduction of fuel into the expansion zone of the turbine 35 and when desired into the supplemental combustion chamber of the tail pipe 60. The thermostatically operated valve ||2 serves to limit the temperature developed in the primary combustion chamber 3| and therefore governs the air-fuel ratio in the combustion chamber. The valve ||2 controls the main air pressure supply line 9| and therefore has an overriding control function affecting the operation of the three fuel metering or control valves A, B and C to limit the temperature to specified maximum values at each of the three points of fuel injection into the power plant. The rotational speed responsive valve lill controls the delivery of actuating air pressure to the metering valve A and to the servo-motors |2||22 which adjust or operate the by-pass valves S9. Accordingly, the valve |01 operates to govern the injection of fuel into the primary combustion chamber 3| to limit rotational speed of the power plant element and further operates to regulate the effective area of the by-pass ducts B5 so that the latter is a function of power plant rotational speed. The pressure bleed valve D is manually regulable by the lever IBI to adjust or control the fuel metering Valve A. This function is performed by bleeding a greater or less amount of air pressure from the line 92. As above described the servo-motors |2||22 of the by-pass valves 69 are supplied with control or actuating air pressure by the line 92 so that the valve D controlled by the manual lever I in turn adjusts the position of the valves 69. Accordingly, the valves 69 are progressively opened as the lever ||l| is moved to reduce the fuel delivery setting below the value for full primary fuel injection. Conversely, the valves 69 are moved toward the closed position when the lever is moved in the direction to increase the rate of fuel injection. The automatic operation or regulation of the valves 69 in the by-pass ducts 65 in conjunction with the functioning of the other elements of the system maintains a substantially correct Q/N ratio preventing overloading of the rst stage compressor and turbining of the second stage compressor |2 at low altitudes and providing for substantially full delivery of compressed air from both compressors and |2 to the primary combustion chamber 3| when the conditions that bring about such overloading and turbining no longer prevail. The energy involved in compressing the air that is by-passed through the ducts 65 is not lost but is recovered at least to a large degree by reintroducing the air under pressure into the expansion zone of the turbine 35 or into the tail pipe 60 to add to the stream of propulsive gases ejected from the nozzle N to form the thrust producing jet.

Since the volumetric flow conditions of the gases in the tail pipe B0 will necessarily vary widely as a result of the automatic selectivity of the relative amounts of fuel injection and air injection at several points in the power plant, as above described, it is found that provision for automatically varying the effective opening of the propulsive nozzle N further produces a beneficial effect upon performance of the power plant, especially when wide ranges of altitudes and airplane speeds are to be negotiated.

In Figure 7 I have shown a suitable control device for the propulsive nozzle N when the latter is of supersonic contour. An annular throat member |31 of streamlined shape supported upon piston rods |36 is axially positioned or moved by pistons |33 operable in cylinders |38 so as to assenzio vary the throat area of :the supersonic nozzle. The-upstream ends 134|A of 'the cylinders |38 .are exposed to throat pressures of the nozzle N by orifices |35 while the downstream vends |32 of the cylinders |38 are exposed through a pipe .I3-I to the pressures in the forward portion |30 of the tail pipe |50.

The yoperation of the variable `area nozzle .device yis that the throat member |31 tends .to close or move rearwardly under-the influence of the propulsive stream flow. -I-Iowever, an excessive restriction of the nozzle 4'throat is averted by pressure differential existing at the orifices v|35 andthe tail pipe portion |30 acting upon the pistons |33 to urge the. throat member |31 to the open or forward position. To accomplish this the orifices |35 are ylocated approximately at the region 'of the propulsive nozzle N which combines with the throat member |31 to form a .point @of mini-mum cross sectional ow area for the gases of combustion in order that these orifices may beinuenced by the `comparatively abrupt pressure drop which occurs .immediatelydownstream from the point of attainment of sonic velocity. Then if the throat member |31 should tend `to closemore than it should, the resultant upstream movement of the plane of sonic velocity will traverse the orices v|35 abruptly reducing the pressure the cylinder ends |34 and restoring the throat member v|31 .to the correct position.

When the foregoing provisions are made, the throat member |31 tends to assume a position of equilibrium which has been found to barely maintain throat sonic velocity as desired in the supersonic nozzle throat .for optimum performance and yet the degree o'f .closure of the throat area'is prevented vfrom producing a choking condition or excessive .flow restriction.

Having described only atypical preferred .form and applicationof the invention, I do .not wish to be limited or restricted to the specic. .details` set forth but wish to reserve to myself .any :features or .modifications that may fall within the scope of the following claims.

I claim.:

l. Ina power .plant having ;a compressor lsystem, a combustion chamber receiving compressed air from said system, and. a turbine driven by the hot gases discharged from the chamber; the combination of a duct for bleedingcompressed air from `an intermediate-'portion of said compressor system, :a 'fuel'.system for introducing fuel into said chamber and including a .tuelcontrol valve, a val-ve -for controlling said duct, .and a manually controllable means for effecting simultaneous operation of said valves comprising a conduit system conducting an actuating pressure fluid, a servo-motor .for operating the fuel control valve and connected i-n .said conduit system yto be operated .by the pressure therein, a servo-motor for operating the `duct controlling valve and vconnected in :said conduit system to be operated by the pressure therein, a master valve in said conduit system for regulating the pressure therein and thereby simultaneously operate the fuel control Valve and the duct controlling valve, and manual means for operating the master valve.

2. In a power plant having .a compressor system, a combustion chamber receiving compressed air from the compressor system and a turbine driven by hot-gases discharged from the chamber; the :combination of afductfor bleeding {com-- pressed air `from an intermediate portion of said compressor system, a fuel system for introducing fu'el under pressure .into said chamber. .andcin-. cluding .a line for conducting` the .fuel tof-saidv chamber, afvalve for controllingf-said line, a. cylinder interposed in said fline, and a pistonfin. said .cylinder connected with .thevalve and acted.l

upon by the fueluowingto vsaid :chamber to :urge

the valve to the closedposition, a valveinv said duct urged toward the open position :bytheair flow 'through' lthe duct, 'and control. meanscomprising a servo-motor :for lurging the first named.

valve to the open position, a servo-motor for urging the second named valve :to the Aclosed .position, a :systemv for conductingactuating .uid pressureto the. servo-"notors, .and aimanually operable `control for bleeding iiuid pressure .from

means-on 'the leading edges- =of .sai'doblade'sior injecting fuel .into 'the casing, and fductmeans for carrying compressed airfromfaniintermediate. portion of `the compressor .systemrto -said passages for discharge into the casing.

4. In a power plant having a compressor-.system, a combustion chamber receiving compressed air from said system, anda turbine Adriven by the hotJ gases from the 1combustion .chamber and including a casing. and a :bladed `rotor operable in the casing to drive the compressor system.; the combination of stator Lblades .in .the casing having internal air. passages and air discharge openings communicating withv` said .passagesand ext-ending `through 'the leading edge .parts of the blades tothe .opposite sides ofthe blades .to discharge 'into .the casing, duct means vfor 'carrying compressed air from an .intermediate .por-tionof the compressor Asystem .to saidpassages 'for fdischarge from said openings, fuel injectors :on .the leading Aedges of .the blades, and means for supplying fuel to .the injectors.

.5.1In a power plant 'havinga compressor system,.a combustion chamber receiving ycompressed air from .said system, and a turbine driven by the hot gases from the :combustion chamber -and including .a casing, and a 4:bladed rotor operable inthe casing to drive the compressor system.; the combination of--Stator blades yin the casing having internal air. passages leading to the tips -of the blades Where .they discharge into the casing and having. air discharge openings extending through'-the leading 'edge parts of Vthe blades from .said passages to the Yopposite sides of the blades .adjacent 'the .leading hedges thereof to discharge .intothe casing, .duct means for carrying compressed. air from an 'intermediate portion of the compressorsystem to said passages for discharge A.from said openings, fuel injectors on the leading edges fof the blades, and means -for supplying fuel to the injectors.

16. In :a power plant having .a compresser system, .a combustion chamber reoeivingcompressed air .from :said system, anda :turbine drivenby the .hot gases'ffrom the combustion chambereand including :a casing,V anda bladed rotor operable in the casing to 'drive the compressor system; the combination 'ofv rows -of- :stator vblades .in the casing, the blades of at least one row having internal air passages and air discharge openings extending from said passages to the opposite sides of the blades adjacent the leading edges thereof to discharge into the casing, fuel injectors on the leading edges of the blades of said row, and means for supplying fuel to said injectors, and duct means for carrying compressed air from an intermediate portion of the compressor system to said passages for discharge from said openings,

7. In a power plant having a compressor system, a combustion chamber receiving the compressed air from said system, and a turbine unit including a casing, a rotor in the casing driven by hot gases from said chamber and driving the compressor system, and a tail pipe extending rearwardly from the rear end of the casing for exhausting the gases from the casing; the combination of means for injecting fuel from the rear end of the rotor into the tail pipe adjacent the rear end of the casing, duct means for carrying compressed air from an intermediate portion of the compressor to said portion of the tail pipe adjacent the casing and discharging the compressed air into said exhaust gases at said rear end of the casing in a plane adjacent and slightly rearward of the point of injection of fuel into the tail pipe, and valve means for controlling the duct means.

8. A control and fuel system for a. power plant having multi-stage compressor means, a combustion chamber receiving compressed air therefrom, and a turbine driven by hot gases received from the chamber and driving the compressor means, said system including a duct for bleeding compressed air from an intermediate portion of the compressor, a fuel line for carrying fuel to the combustion chamber, a metering valve controlling the fuel line, a valve for said duct, and a single control for said valves including fluid pressure actuated means for operating the metering valve, fluid pressure actuated means for operating the duct valve, and a manually operable valve for controlling the application of actuating fluid pressure to both of said fluid pressure actuated means.

9. A control and fuel system for a power plant having multi-stage compressor means, a combustion chamber receiving compressed air therefrom, and a turbine driven by hot gases received from the chamber and driving the compressor means, said system including a duct for carrying compressed air from an intermediate portion of the compressor to the turbine for introduction thereinto, a fuel line for carrying fuel to the combustion chamber, a fuel line for carrying fuel to the turbine for introduction thereinto, a metering valve for each of said fuel lines, fluid pressure actuated means for operating the metering valves, a valve for said duct, fluid pressure actuated means for operating the duct valve, and manually operable means for controlling the application of actuating fluid pressure to the three uid pressure actuated means.

10. A control and fuel system for a power plant having multi-stage compressor means, a combustion chamber receiving compressed air therefrom, and a turbine driven by hot gases received from the chamber and driving the compressor means, said system includingr a duct for bleeding compressed air from an intermediate portion of the compressor, a fuel line for carrying fuel to the combustion chamber, a metering valve controlling the fuel line, a valve for said duct, and

a single control for said valves including fiuid pressure actuated means for operating the metering valve, iiuid pressure actuated means for operating the duct valve, means responsive to the temperatures in the combustion chamber for controlling the application of actuating fluid to both of said fluid pressure actuated means, and a manually operable valve for controlling the application of actuating fluid pressure to both of said fluid pressure actuated means.

11. A control and fuel system for a power plant having multi-stage compressor means, a combustion chamber receiving compressed air therefrom, and a turbine driven by hot gases received from the chamber and driving the compressor means, said system including a duct for bleeding compressed air from an intermediate portion of the compressor, a valve for controlling the duct, an operating means for the valve, a manually operable control acting directly upon the operating means, and means responsive to the rotational speed of the turbine and compressor for regulating said operating means.

12. In a power plant having a compressor` system, a combustion chamber receiving compressed air from said system, a turbine unit including a turbine driven by the hot gases from the combustion chamber and a tail pipe for eX- hausting the gases from the turbine; the combinatio-n of means for introducing fuel into the tail pipe, the combustion of the fuel from said means in the tail pipe causing variations in the volumetric new and pressure in the tail pipe `under different conditions of operation, a propulsive nozzle for the outlet of the tail pipe, a member movable in the nozzle to vary the effective flow passage area thereof, and means operable in response to the differentials in pressure in the nozzle and a point in the tail pipe adjacent the region of introduction of fuel therein by said fuel introducing means for moving the member including a cylinder and piston device for moving the member, the cylinder of said device having one end in communication with the nozzle, and a pipe having one end in communication with the other end of the cylinder and having its other end in communication with the tail pipe at said point.

NATHAN C. PRICE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,111,498 Retter Sept. 22, 1914 2,112,391 AnXionnaz Mar. 29, 1938 2,149,510 Darrieus Mar. 7, 1939 2,219,994 Jung Oct. 29, 1940 2,236,426 Faber Mar. 25, 1941 2,238,905 Lysho-lm Apr. 22, 1941 2,243,467 Jendrassik May 27, 1941 2,297,446 Zellbeck et al Sept. 29, 1942 2,356,557 Anxionnaz et al. Aug. 22, 1944 2,402,363 Bradbury June 18, 1946 2,404,767 Heppner July 23, 1946 2,458,600 Imbert et al Jan. 11, 1949 2,464,724 Sdille Mar. 15, 1949 2,487,588 Price Nov. 8, 1949 2,489,683 vStolker Nov. 29, 1949 2,520,434 Robson Aug. 29, 1950 2,566,961 Poole Sept. 4, 1951 FCREIGN PATENTS Number Country Date 586,719 Great Britain Mar. 28, 1947 919,004

France Nov. 18, 1946 

